Biostatus and Distribution

This adventive ladybird of variable appearance was first found in 2016 in Auckland. Its native range is Central and Eastern Asia, but it was deliberately released into USA, Europe, South America and Middle East and has spread to other countries. It feeds mainly on aphids, but also feeds on other small insects including ladybirds. In New Zealand, it has been observed feeding on giant willow aphid. It is also regarded as a pest of some fruit crops.

Conservation status: This adventive ladybird is now (2018) present throughout the North Island and is in the South Island, Nelson, Marlborough, Canterbury and Otago. It will probably soon spread to the rest of the South Island. It may assist with control of some aphid pests, but may also harm native and beneficial insects.

Life Stages and Annual Cycle

Adults of the harlequin ladybird are about 5-8 mm long. They are extremely variable in appearance, hence the name, harlequin ladybird and some of its other common names. It may be red or orange with zero to 21 black spots. It may all black or black with four or two orange or red spots. Most individuals have white on the pronotum (first segment behind the head). The black spots on the pronotum usually form an ‘M’ shape when seen from the top and looking forward. There are three pairs of legs that are usually reddish-brown. Under the elytra is a pair of wings used for flying. The small head is mainly black and white. It has a pair of compound eyes and two short brown antennae.

Female ladybirds lay yellow eggs near infestations of prey. A larva hatches from each egg. There are four larval instars (stages). As the larva grows, it moults (changes skin). The newly hatched larva is dark grey with short black scoli (flesh extensions that look like spines), and black legs, head and prothorax (first segment with legs). The second instar larva is similarly coloured, but with white/yellowish scoli on the upper side of the first abdominal segment, that extends faintly to the to fourth segment. The scoli on the third instar larvae are more strongly coloured yellow and there are traces of a lateral white line. The colouration of the Fourth instar is stronger and more extensive. Seen from the top, the lateral scoli on abdominal segments 1-5 and the central scoli on segments 1, 4 & 5 are yellow-orange. Seen from the side there is a broken white line on the thorax and abdomen. A distinctive feature of the scoli on the four rows on the top of the body is that they each have three spines. There are three pairs of brown legs. Larvae also use the tip of the abdomen for holding onto the substrate on which they are walking.

The tip of the abdomen also holds the larva to the surface during moulting both to another larval instar and to a pupa. When the fourth larval instar is fully grown, it attaches itself to a sheltered place on a plant. The pupa is dark brown with dark patches on the abdomen, wing buds and thorax. Adults hatch from pupae and mate. The length of time of each life stage depends on temperature, being shorter at higher temperatures.

Annual cycleThe ladybird overwinters as adults. They may gather in small or large groups to hide in sheltered places. In North America there are two or more overlapping generations per year with adult activity starting when temperatures begin to reach 12°C. In Auckland they were active in early September and colonies were still in trees in June. Females can lay 20-30 eggs per day and breed throughout their adult life, with an individual producing 1600 to 3800 eggs.

Walking and flyingBoth adult and larval stages of this ladybird have three pairs of legs that can be used for walking. Larvae also use the tip of the abdomen for holding onto the substrate. Adults have wings and can fly. They are known to fly long distances.

Recognition

The appearance of adult harlequin ladybirds is very variable, which often makes it difficult to distinguish from some other species in New Zealand. However, harlequin ladybird larvae are sufficiently distinctive for the second, third and fourth instar larvae to be reliably identified.

AdultsAdult harlequin ladybirds may be red or orange with zero to 21 black spots. They may be all black or black with four or two orange or red spots. Most individuals have white on the pronotum (first segment behind the head). The black spots on the pronotum usually form an 'M' shape when seen from the top and looking forward. One consistent feature is that the legs are reddish-brown.

The following adult ladybirds are superficially like some forms of the harlequin ladybird, but can be distinguished using the features described below.

The adult leaf eating hadda beetle, Epilachna vigintioctopunctata is orange red with 26 black spots of variable size. There are four distinguishing feature. The head, prothorax (first part of the middle body) and elytra (wing covers) are covered with short fine hairs. The head and prothorax are orange with black marks. On the elytra the pairs of spots by the midline of the second and fourth transverse rows may join each other.

Adult large spotted ladybirds, Harmonia conformis typically are orange with many black spots, but may be almost black. There are several useful distinguishing features. The dark and spotted forms have some orange-brown on their head and prothorax. The size of spots varies, usually the pairs of spots by the midline of the elytra of the first and third transverse rows are joined. In addition, the black marks on the prothorax form two 'U' shapes when seen from the top and looking forward. These marks may look like a 'W'.

Adult antipodean ladybirds, Harmonia antipodum have variable black marks on their elytra and have an orange-brown underside. The head and pronotum are orange and black and the pair of black marks on the pronotum form two simple lines.

Adult eleven-spotted ladybirds, Coccinella undecimpunctata are easily recognised. The underside of the body is black as are their legs. They have predominately a black head and prothorax with small areas of white. The red elytra have 9 or 11 black spots which may vary in size and position.

Typical adult two-spotted ladybirds, Adalia bipunctata are easily recognised, but there are some very different colour forms. One distinguishing feature from adult harlequin ladybirds are the black legs. In the red form with two black spots, the shape and size of the spots can vary. In colour forms that are black with red or orange patches, patches of colour come right to the front of the elytra, whereas similar harlequin ladybirds the front spots do not reach the front of the elytra.

Adult variable ladybirds, Coelophora inaequalis are red and black. The pronotum is red and black, and in New Zealand the black marks on the elytra tend to form a cross.

Adult fungus-eating ladybirds, Illeis galbula are yellow and black. The pronotum is yellow and black and the legs are black.

Adult southern ladybirds, Cleobora mellyi are red to yellow orange with black zig-zag marks on the elytra. The pronotum is similarly coloured and the black marks are not 'M' shaped.

Adults of cardinal ladybird, Rodolia cardinalis and Koebele's ladybird, Rodolia koebelei and red and black and the elytra and pronotum are covered with short setae (hairs).

Adult Orange-spotted ladybirds, Coccinella leonina, are black with orange spots. The legs are black. The intensity of the black on the elytra and pronotum varies and the spots vary from pale to dark orange as well as varying in size and shape. The seven spots on each elytrum that are arranged in three transverse rows. The front two on each elytrum reach the edge by the pronotum.

LarvaeThe second instar larva is dark grey with white/yellowish scoli on the upper side of the first abdominal segment, that extends faintly to the fourth segment. The scoli on the third instar larvae are more strongly coloured yellow and there are traces of a lateral white line. The colouration of the fourth instar is stronger and more extensive. Seen from the top, the lateral scoli on abdominal segments 1-5 and the central scoli on segments 1, 4 & 5 are yellow-orange. Seen from the side there is a broken white line on the thorax and abdomen. A distinctive feature of the scoli on the four rows on the top of the body is that they each have three spines. The three-spined scoli can be seen on the larval skin at the base of the pupa.

The larvae of the large spotted ladybird, Harmonia conformis are superficially similar, being dark grey with yellow scoli. However, the areas of yellow are arranged differently. Another distinguishing feature is that the 4 central rows of abdominal scoli have two spikes, not three as found on the harlequin ladybird.

Natural Enemies

No natural enemies of the harlequin ladybird have been reported in New Zealand.

In other countries the harlequin ladybird is subject to a variety of pathogens, parasites and parasitoids. One parasitoid, Dinocampus coccinellae (Shrank, 1802) (Hymenoptera: Braconidae) of adult ladybirds that is present in New Zealand is known to attack the harlequin ladybird. As is a soil pathogen, Cordyceps bassiana Z.Z. Li, C.R. Li, B. Huang & M.Z. Fan (Ascomycota: Sordariomycetes: Hypocreales: Cordycipitaceae) (also called Beauveria bassiana). There are also reports that it will eat its own eggs and larvae.

Host Plants

No feeding on plants has yet been reported in New Zealand, but in other countries, adult harlequin ladybirds have been reported to feed on the sap of soft fruit such as grapes and apples and pears. If they are present in the harvested grapes they release chemicals that alter the taste of the juice and wine.

Prey/Host

In New Zealand the Harliquin ladybird has been found feeding on the giant willow aphid, Tuberolachnus salignus (Hemiptera: Aphididae). It has occasionally been found associated with other aphids.

The giant willow aphid is a major pest of willow trees. The Harlequin ladybird is now its main predator. By 2018 in Auckland, it had substantially reduced populations of the aphid on willow trees that I have been observing.

In other countries the harlequin ladybird mainly feeds on aphids and scale insects. They may also eat Thysanura species and mites and eggs of butterflies and moth eggs. When other foods are scarce, it is reported to eat other various Coccinellidae species as well as its own eggs and larvae.

Additional Information

Diverse habits of 'ladybirds'Not all ladybirds eat insects; some feed on mites. Other species eat plant leaves and are pests especially in some tropical countries, whereas other ladybirds feed on fungi. One of these, Illeis galbula (Mulsant, 1850), from Australia feeds on powdery mildew fungi. In New Zealand it is common on pumpkins and other cucurbits, plants that are commonly infected by powdery mildews. A plant feeding ladybird, hadda beetle (Epilachna vigintioctopunctata (Fabricius, 1775)) recently established in Auckland feeds on plants in the Solanaceae (potato family).

Monitoring the spread of Harlequin ladybird in New ZealandThe harlequin ladybird was first detected in New Zealand in Autumn 2016. And by winter 2016, it had only been found in Auckland. Nature Watch has organised a project to monitor the spread of harlequin ladybirds in New Zealand. Full details of the project can be found at http://naturewatch.org.nz/projects/nz-ladybird-watch.

Biological control of pestsThe harlequin ladybird was released into North America for the biological control of aphids. The first release of the ladybird into the USA was in 1916, but it did not establish until 1988 (Wikipedia 2016). It was more recently also released into Continental Europe for use in greenhouse and outdoor crops. It has since spread to other countries. In the USA it is reported to give good control of some aphid species. The releases into USA and Europe were made before the implementation of the current regulations about release of potential biological control agents. These days before an organism can be released into New Zealand for biological control of a pest, it needs to be assessed for its potential to harm native and beneficial invertebrates, vertebrates and plants. Any potential adverse effects are compared with the potential benefits.

Reports of the harm caused by the harlequin ladybird to beneficial animals and plants means that it would not be deliberately released into New Zealand.

Pest status (Wikipedia, 2016 October)The harlequin ladybird is regarded as a pest, because they have a tendency to overwinter indoors and when frightened or squashed they produce an unpleasant odour and stain left by their bodily fluid. They also have tendency to bite humans. In Europe and USA there is concern about its impact on indigenous species of ladybirds. Its voracious appetite enables it to outcompete them and it even eats other species of ladybirds. It is also a minor agricultural pest contaminating crops of tender fruits and grapes. The contamination of grapes by this beetle can alter the taste of wine.

Distribution (Wikipedia, 2016 October)Harmonia axyridis is native to central and eastern Asia from central Siberia, Kazakhstan, and Uzbekistan in the west, through Russia south to the Himalayas and east to the Pacific coast and Japan, including Korea, Mongolia, China, and Taiwan. As a biocontrol agent for aphids and scale insects was released into greenhouses, crop fields, and gardens in many countries, including the United States and parts of Europe. The species is now established in the United States, Canada, Argentina, Brazil, Italy, the United Kingdom, Denmark, Sweden, Norway, Finland, the Netherlands, Belgium, Luxembourg, France, Germany, the Czech Republic, Hungary, Croatia, Poland, and South Africa.

It has also been reported from several countries in South America.

Pheromones (Wikipedia 2016 October)Adult harlequin ladybirds release volatile chemical, pheromones. This enables them to aggregate in the autumn, when large numbers gather together. These chemicals are being used by the makers of harlequin ladybird traps. However, many cues are visual, both at long distance (picking out light-coloured structures that are distinct from their surroundings) and short distances (picking out pre-existing aggregations to join), while non-volatile long-chain hydrocarbons laid down by previous aggregations also play a significant role in site selection. Both are more important than volatile pheromones.